This invention relates to a system for detecting fuel injection conditions, such as fuel injection timing and/or period, in a diesel engine.
Diesel engines have fuel injection nozzles or fuel injectors to discharge fuel into combustion chambers. Usually, the nozzle is provided with a valve needle which is lifted intermittently to inject fuel. Lift of the valve needle, thus, reflects the timing and period of fuel injection.
In feed-back control of fuel injection timing and/or rate, the actual fuel injection timing and/or rate needs to be sensed. The fuel injection rate can be derived essentially from fuel injection period and engine rotational speed.
Accordingly, a new sensor is being developed which detects lift of the valve needle and generates a signal indicative thereof. However, the output of such a lift sensor includes noise and adverse components resulting for a variety of reasons.